I've had this car in and out the shop for weeks and we cant seem to figure the problem out. The car just randomly decides too not start and when it doesn't start, it usually won't for hours after sitting or until right after i tow it. I first replaced the battery and the car started and ran for a couple days but then wouldn't start again. I then replaced the starter (thankfully for free) and it ran again for a couple days but wouldn't start again. I replaced the ground to the started and it again, ran for a while but wouldn't start again. There are no codes popping up for the sensors, brand new starter, new battery, no codes for sensors, new ground, what could be wrong? if anyone has any ideas it'd be very helpful.

 

Hello Zachary, I could not tell from your post if the car is not turning over or if the car is not starting while turning over. If the problem is the engine is not cranking over I may have some suggestions for you. Kind of sounds like that is your problem because you said you have new battery and new starter. My niece has an 05 which intermittently would not turn over I did extensive research into this problem through multiple websites. The problem with it being intermittent is it would seem like every time I did something it would work for a few days or a few hours and then start failing again. I narrowed the problem down to one of two things. It had to be either the neutral safety switch or a problem in the engine control computer. Since both are a little pricey to replace I opted for a non-Orthodox repair. I bypassed the neutral safety circuit at the starter relay in the fuse box. Now this was a last-ditch repair that only cost about $10 in parts. So far this repair has worked flawlessly except for the one drawback that the car will start in gear. Feel free to contact me and I can go over with you all the research I did and why I came to the conclusions to do what I did. Good luck have a good day Jeff

 

So the neutral safety switch didn't pop a code? Well I guess I can try and bypass it, if you could just briefly explain how or what sites to visit I should be able to figure it out, thanks

 

Hello Zachary, a couple things; one is have you tried replacing the original starter relay in the fuse box with a new one. I have found the factory relays to not be that reliable. Some people suggest swapping one relay for another, I suggest replacing it with a new one. They're not that expensive $12-$15. It is the number one relay, closest to engine in the engine compartment fuse box.
The relay set up I designed utilized an original relay broken apart so I could solder wires directly to those terminals which allowed no modification to factory wire harness and allows the ability to simply unplug my adapter and go back to original if ever needed.
The relay set up I used utilized two standard Bosch relays since they are less expensive and more reliable.

there are no codes as far as I know that indicate any problems with the neutral safety switch. And I'm not absolutely sure that that's where the problem lies for a couple reasons the circuit goes from the engine control module i.e." ECM" to the neutral safety switch then back through the ECM up to the starter relay. And the problem could be anywhere in that circuit. If I had access to a factory service manual, not a Haynes manual I could easily isolate the circuit. Let me know and I will diagram the circuit for you have a good day

 

If my crank shaft sensor is bad will that cause a no crank start?

 

I'm not sure what you mean by "no crank start". Does the engine not turn over, or does it turn over and not start? A bad crankshaft sensor can cause frustrating intermittant no start situations without turning on the CEL or setting a code. The engine will still turn over, but the injectors won't receive a signal to pulse.